Measurement techniques utilizing ultrasonic waves have advantages in being able to be employed in-situ and have substantially no permanent effect on a sample. However, current ultrasonic non-destructive evaluation (NDE) and non-destructive test (NDT) techniques typically give indirect indications of variations of mechanical properties and morphological conditions within a sample. Moreover, empirical correlations and calibration factors may also need to be established for each sample material. For example, ultrasonic NDE/NDT techniques are used to measure such quantities as time of flight and attenuation, from which information about phase velocity (itself dependent on stiffness and density) and discontinuities (such as cracks and boundaries) may be inferred. However, the empirical correlations, calibrations factors, and other assumptions are potentially significant sources of error in the inferences made.